*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
*::before{ 
    box-sizing: border-box;
}
*::after{
    box-sizing: border-box;
}
#html{
    /* 文字太长会造成横向滚动条，下面代码为的是自动换行 */
    position: fixed;
    top: 0;
    left: 0;
    width: 45vw;
    height: 100vh;
    border: 1px solid black;
    overflow-y: auto;
}
#html::-webkit-scrollbar{
    display: none;
    
}
.demo{
    position: fixed;
    right: 0;
    top: 0;
    width: 55vw;
    height: 100vh;
}
#buttons{
    position: fixed;
    left: calc(45vw - 60px);
    top: 0;
    z-index: 10;
    display: flex;
    flex-direction: column;
    margin-top: 10px;
    margin-right: 10px;
    
}
#buttons > button{
    margin-bottom: 10px;
    padding: 4px 8px;
    background-color: #ffcb00;
}
